<template>
  <div :class="classes">
    <label v-if="label || $slots.label" :class="[prefixCls + '-label']" :for="labelFor" :style="labelStyles">
      <slot name="label">{{ label }}{{ FormInstance.colon }}</slot>
    </label>
    <div :class="[prefixCls + '-content']" :style="contentStyles">
      <slot></slot>
      <transition name="fade">
        <div v-if="validateState === 'error' && showMessage && FormInstance.showMessage" :class="[prefixCls + '-error-tip']">{{ validateMessage }}</div>
      </transition>
    </div>
  </div>
</template>
<script>
import AsyncValidator from 'async-validator';
import Emitter from '../../mixins/emitter';

const prefixCls = 'ivu-form-item';

function getPropByPath(obj, path) {
  let tempObj = obj;
  path = path.replace(/\[(\w+)\]/g, '.$1');
  path = path.replace(/^\./, '');

  let keyArr = path.split('.');
  let i = 0;

  for (let len = keyArr.length; i < len - 1; ++i) {
    let key = keyArr[i];
    if (key in tempObj) {
      tempObj = tempObj[key];
    } else {
      throw new Error('[iView warn]: please transfer a valid prop path to form item!');
    }
  }
  return {
    o: tempObj,
    k: keyArr[i],
    v: tempObj[keyArr[i]]
  };
}

export default {
  name: 'FormItem',
  mixins: [Emitter],
  props: {
    label: {
      type: String,
      default: ''
    },
    labelWidth: {
      type: Number
    },
    prop: {
      type: String
    },
    required: {
      type: Boolean,
      default: false
    },
    rules: {
      type: [Object, Array]
    },
    error: {
      type: String
    },
    validateStatus: {
      type: Boolean
    },
    showMessage: {
      type: Boolean,
      default: true
    },
    labelFor: {
      type: String
    }
  },
  data() {
    return {
      prefixCls: prefixCls,
      isRequired: false,
      validateState: '',
      validateMessage: '',
      validateDisabled: false,
      validator: {}
    };
  },
  mounted() {
    if (this.prop) {
      this.dispatch('iForm', 'on-form-item-add', this);

      Object.defineProperty(this, 'initialValue', {
        value: this.fieldValue
      });

      this.setRules();
    }
  },
  beforeDestroy() {
    this.dispatch('iForm', 'on-form-item-remove', this);
  },
  methods: {
    setRules() {
      let rules = this.getRules();
      if (rules.length && this.required) {
        return;
      } else if (rules.length) {
        rules.every(rule => {
          this.isRequired = rule.required;
        });
      } else if (this.required) {
        this.isRequired = this.required;
      }
      this.$off('on-form-blur', this.onFieldBlur);
      this.$off('on-form-change', this.onFieldChange);
      this.$on('on-form-blur', this.onFieldBlur);
      this.$on('on-form-change', this.onFieldChange);
    },
    getRules() {
      let formRules = this.FormInstance.rules;
      const selfRules = this.rules;

      formRules = formRules ? formRules[this.prop] : [];

      return [].concat(selfRules || formRules || []);
    },
    getFilteredRule(trigger) {
      const rules = this.getRules();

      return rules.filter(rule => !rule.trigger || rule.trigger.indexOf(trigger) !== -1);
    },
    validate(trigger, callback = function() {}) {
      let rules = this.getFilteredRule(trigger);
      if (!rules || rules.length === 0) {
        if (!this.required) {
          callback();
          return true;
        } else {
          rules = [{ required: true }];
        }
      }

      this.validateState = 'validating';

      let descriptor = {};
      descriptor[this.prop] = rules;

      const validator = new AsyncValidator(descriptor);
      let model = {};

      model[this.prop] = this.fieldValue;

      validator.validate(model, { firstFields: true }, errors => {
        this.validateState = !errors ? 'success' : 'error';
        this.validateMessage = errors ? errors[0].message : '';

        callback(this.validateMessage);

        this.FormInstance && this.FormInstance.$emit('on-validate', this.prop, !errors, this.validateMessage || null);
      });
      this.validateDisabled = false;
    },
    resetField() {
      this.validateState = '';
      this.validateMessage = '';

      let model = this.FormInstance.model;
      let value = this.fieldValue;
      let path = this.prop;
      if (path.indexOf(':') !== -1) {
        path = path.replace(/:/, '.');
      }

      let prop = getPropByPath(model, path);

      //                if (Array.isArray(value) && value.length > 0) {
      //                    this.validateDisabled = true;
      //                    prop.o[prop.k] = [];
      //                } else if (value !== this.initialValue) {
      //                    this.validateDisabled = true;
      //                    prop.o[prop.k] = this.initialValue;
      //                }
      if (Array.isArray(value)) {
        this.validateDisabled = true;
        prop.o[prop.k] = [].concat(this.initialValue);
      } else {
        this.validateDisabled = true;
        prop.o[prop.k] = this.initialValue;
      }
    },
    onFieldBlur() {
      this.validate('blur');
    },
    onFieldChange() {
      if (this.validateDisabled) {
        this.validateDisabled = false;
        return;
      }

      this.validate('change');
    }
  },
  computed: {
    classes() {
      return [
        `${prefixCls}`,
        {
          [`${prefixCls}-required`]: this.required || this.isRequired,
          [`${prefixCls}-error`]: this.validateState === 'error',
          [`${prefixCls}-validating`]: this.validateState === 'validating'
        }
      ];
    },
    // form() {
    //    let parent = this.$parent;
    //    while (parent.$options.name !== 'iForm') {
    //        parent = parent.$parent;
    //    }
    //    return parent;
    // },
    fieldValue() {
      const model = this.FormInstance.model;
      if (!model || !this.prop) {
        return;
      }

      let path = this.prop;
      if (path.indexOf(':') !== -1) {
        path = path.replace(/:/, '.');
      }

      return getPropByPath(model, path).v;
    },
    labelStyles() {
      let style = {};
      const labelWidth = this.labelWidth === 0 || this.labelWidth ? this.labelWidth : this.FormInstance.labelWidth;

      if (labelWidth || labelWidth === 0) {
        style.width = `${labelWidth}px`;
      }
      return style;
    },
    contentStyles() {
      let style = {};
      const labelWidth = this.labelWidth === 0 || this.labelWidth ? this.labelWidth : this.FormInstance.labelWidth;

      if (labelWidth || labelWidth === 0) {
        style.marginLeft = `${labelWidth}px`;
      }
      return style;
    }
  },
  watch: {
    error: {
      handler(val) {
        this.validateMessage = val;
        this.validateState = val ? 'error' : '';
      },
      immediate: true
    },
    validateStatus(val) {
      this.validateState = val;
    },
    rules() {
      this.setRules();
    },
    required(n, o) {
      this.isRequired = n;
      if (o && !n) {
        this.resetField();
      }
    }
  },
  inject: ['FormInstance']
};
</script>
